1. Field of the Invention
This invention relates to a socket type electrical connector which includes: a molded connector body having an inserting recess into which a mating plug-type electrical connector is inserted, and a predetermined number of contact pins embedded therein; and a shield cover covering the molded connector body, and which connector is fixedly secured, for instance, to a wiring board built in an electronic apparatus.
2. Related Art
A typical example of an electrical connector of this type is as shown in FIGS. 15 through 20. The electrical connector 70 comprises a box-shaped molded connector body 71, and a shielding cover 80. The connector body 71 has an inserting recess 73 into which a mating plug-type electrical connector 90 (FIGS. 18 through 20) is inserted. As shown in FIG. 17, the connector body 71 has two guide pins 74 and a predetermined number of contact pins 75 (sixteen contact pins 75 in the connector shown in FIG. 17) which are embedded therein. The shielding cover 80 is fixedly secured to the connector body 71 in such a manner that it substantially covers the upper and right and left surfaces of the connector body 71.
The shielding cover 80, as shown in FIG. 16 which is an unfolding diagram of the shielding cover 80, comprises: a top plate 81 with two cantilevered contact tongue pieces 85 and 85 which are V-shaped in section; a pair of side plates 83 and 82 which are extended downwardly from the right and left ends of the top plate 81; and rear retaining plates 84a, 84b and 84c which are extended from the rear ends of the top plate 81 and the side plates 83 and 82, respectively. The top plate 81 has a pair of pit-like protrusions on its lower surface, and the side plates 82 and 83 have locking windows 82a and 83a, respectively. Those plates are bent through 90.degree. along the one-dot chain lines in FIG. 16 to form the shielding cover 80. The shielding cover 80 thus formed is engaged with the connector body 71 from above in such a manner that the protrusions 89 and 89 of the top plate 81 are engaged with an engaging groove 79 formed in the connector body 71, and the locking windows 82a and 83a of the side plates 82 and 83 are engaged with fixing protrusions 76 and 76 formed on both side surfaces of the connector body 71. Thus, the shielding cover 80 has been fixedly secured to the connector body 71.
When the shielding cover 80 is combined with the connector body 71 in the above-described manner, the contact tongue pieces 85 and 85 of the shielding cover 80 are partially allowed to go into rectangular windows 77 and 77, respectively, which are formed in the upper surface of the connector body 71. Hence, when the mating connector 90 is inserted into the inserting recess 73 of the connector body 71, the contact tongue pieces 85 and 85 are elastically pushed against a shielding cover 95 mounted over the mating connector 90.
Hence, external noise is grounded through the shielding cover 95 of the mating connector 90, the contact tongue pieces 85, the shielding cover 80, legs 86 of the latter 80, a wiring board in an electronic apparatus which is connected to the connector 70 and the housing of the electronic apparatus.
In FIGS. 15 through 20, reference numerals 78 and 88 designate locking holes which are formed in the connector body 71 and the shielding cover 80, respectively. Those locking holes 78 and 88 are engaged with a locking protrusion 96 of the mating connector 90 to prevent the mating connector 90 from coming off the connector 70. The locking protrusion 96 of the mating connector 90 is so designed that it is moved in and out by operating an operating button 97.
In the above-described electrical connector 70, the shielding cover 80 covers the connector body 71. The contact tongue pieces 85 and 85 bent downwardly are extended through the upper wall of the connector body 71 into the inside of the connector body 71 so that the shielding cover 80 of the connector 70 is electrically conducted to the shielding cover 95 of the mating connector 90.
However, the conventional electrical connector 70 thus constructed is disadvantageous in the following points:
(1) The connector 70 is not sufficiently shielded, because the shielding cover 80 covers only the top and right and left sides of the connector body 71.
(2) There are gaps around the contact tongue pieces 85 and 85. Hence, not only dust but also radiation noise may go into the connector 70 through the gaps.
(3) In order to overcome the difficulty described in the above paragraph (1), instead of the U-shaped shielding cover, a box-shaped shielding cover has been proposed in the art. However, the box-shaped shielding cover gives rise to another problem. That is, in the case where the box-shaped shielding cover is formed merely by bending a metal plate, the front end portion of the connector where the connector inserting recess opens may be deformed when the mating connector 90 is engaged with or disengaged from the connector 70.
(4) The shielding cover 80 has only two contact tongue pieces 85 and 85 in its upper plate. This means that the number of electrical contact points and the electrical contact area of the connector 70 are both small; that is, the connector 70 is relatively low in electrical conductivity with the shielding cover of the mating connector.